BenQ LH850ST vs Optoma ZH450ST Short Throw Laser Projector Shootout

According to a survey of simulator owners and buyers the #1 thing they want is a projector that is easy to set up. With short throw projectors, it is more important to get the projector mounted in the correct location to ensure that the image properly fills the screen or space properly. There are three big differences between these two projector models.

With short throw lenses, any mounting errors are magnified because a small tilt on the projector if its mounted off-center creates a bigger distortion of the image. Since Murphy’s Law is still alive and well, the BenQ LH850ST has twice as much keystone correction (30%) than the Optoma ZH450ST (15%). The BenQ LH850ST also has a nice corner fit function that enables you to drag the corners of the image exactly where you want them to properly fill up the screen.  The projector then cleans up the image to make it as sharp as possible. The LH850ST has quite a bit of corner fitting adjustments that make it much easier to handle more challenging installations such as oversized or odd shaped screen sizes.

The BenQ LH850ST has the advantage of being able to create a larger image on a wall or screen without tilting the projector. This is due to the way the projector lens is “offset” or shifting the image up/down on the wall. The Optoma ZH450ST has a higher offset which is better in meeting room use, but a disadvantage when used in a projection mapping or simulation project. In a room where both projectors are ceiling mounted 8 feet from the ground, the BenQ LH850ST can create an image around just over 7.2 feet high, while the Optoma ZH450ST can only create an image 6.9 feet high without any tilting.

Like things simple and reliable? The BenQ LH850ST uses a standard power cable that’s easily hidden. The Optoma ZH450ST has a power brick, so to get power to the projector, you have to connect a power cable to the brick, safely secure the brick, then run the special power cable to the projector.

Many higher brightness projectors are optimised only for brightness and sacrifice colour accuracy to achieve a higher lumen rating. The BenQ LH850ST is designed first for colour accuracy and is specified to the same Rec. 709 colour standard specification that is required in flat screen televisions. The projector also supports HDR10 and HLD, and also has a simulation mode that enables brighter and more vibrant reds and yellows for projects like Battle Kart Racing, where dozens of BenQ immersive and simulation projectors are blended together to create a massive real life video game environment. The LH850ST also comes pre-calibrated so that the white point is the same from projector to projector, which can save hours of work when blending a projector.

Figure 1- Battle Kart uses dozens of blended BenQ short throw projectors to create a virtual indoor racing track.

Optoma doesn’t provide any colour accuracy specifications on the ZH450ST and is not calibrated at the factory.  Therefore, you’ll have to calibrate the and adjust the projector colours yourself to effectively blend multiple projectors.

What if you want to use it with a different aspect ratio screen, such as a narrower 4:3 screen or even a square 1:1 aspect ratio screen? Whether its blending multiple projectors together for a unique shape or just wanting to make a bigger visual impact, the BenQ LH850ST has the ability to natively support all the common non-native aspect ratios used in simulators including 16:10, 4:3, and even 1:1. What is really nice is that the projector reconfigures the picture to eliminate any distortion on the new aspect ratio (no squished pictures) and will tell your PC exactly how to feed it the resolution it needs, so you don’t have to waste your time re-programming your graphics card. The Optoma ZH450ST doesn’t support 1:1 aspect ratio and doesn’t update your PC when you change the aspect ratio of your picture. So, with the Optoma, you’ll have to reprogram your graphics card to the correct resolution to avoid a distorted image.

Figure 2- The BenQ LH850ST can easily support different aspect ratios without squishing the screen.

Just like wide angle lenses on cameras, short throw lenses on projectors can be trickier to focus. To make it easier, the BenQ LH850ST has an integrated camera sensor that enables you to re-focus the projector with a touch of the button on the remote. The projector will display a test pattern, then use its AI engine to automatically make the tiny adjustments needed for a crisp sharp picture in just a few seconds. This is especially helpful in a commercial golf simulation setup with multiple projectors, or if the projector is mounted in a difficult to reach or hidden location. The Optoma ZH450ST uses a traditional focus ring that requires you to physically adjust the focus manually, which might require you to climb a ladder. Bad ladder joke – why did the musician need a ladder? To reach the high notes. OK – let’s move on to brightness.

At first glance, both projectors look to have similar brightness ratings when you look at the “lumen” specification. But in 2024, lumens can mean different things to different brands. Until recently, every projector brand used the conservative ANSI lumens that measured the average brightness on the screen. Then a few years ago, brands started to come up with other lumen measurements, such as ISO lumens, which isn’t as conservative and measures fewer points of the screen so some projectors using this standard have higher lumen specifications. The BenQ LH850ST projector brightness is rated at 4000 ANSI lumens. But the Optoma ZH450ST doesn’t reference any industry standards when rating their lumens, so it’s a bit vague as to how bright the projector really is. For example, the specification sheet on the Optoma website shows 4200 “lumens” but on the Projector Central Review, they indicate that “Brightness is well under its 4200 ANSI lumen claim”, and Projector Reviews review shows a specification of 3500 ANSI lumens in its review of the unit.

Both projectors come with a free device management software solution and can use a Wi-Fi dongle for wireless projection control. They each have a three-year warranty, but the light source warranty on the BenQ LH850ST is 20,000 hours, while the Optoma LH850ST is only 12,000 hours. If you’re thinking about doing an outdoor projection mapping project, the BenQ LH850ST has a 40% larger security bar to keep your projectors from walking away.